Abstract

Microsomal oleic acid desaturase (FAD2) catalyzes the first committed step of the biosynthesis of polyunsaturated fatty acids via extra-plastidial desaturation of oleic acid to linoleic acid. In the regulatory mechanism controlling seed-specific SeFAD2 expression, trans-activation of the seed-specific SeFAD2 promoter is mediated by the SebHLH transcription factor (Kim et al. in Plant Mol Biol 64:453–466, 2007). In this study, a protein interacting with SebHLH was isolated from yeast two-hybrid analysis. The protein shares approximately 80% sequence identity with other putative casein kinases and was named SeCKI (Sesame Casein Kinase I). SeCKI transcripts were predominantly expressed in developing sesame seeds and were induced approximately threefold by exogenous application of ABA. eGFP:SeCKI fusion protein was localized to the nucleus. The SeCKI protein specifically bound to SebHLH. The SeCKI protein was autophosphorylated in a calcium-independent manner and transphosphorylated the SebHLH protein. Both the SebHLH and the SeCKI genes or both the SebHLH and mutated SemCKI (K182G) genes, under the control of CaMV 35S promoter, and the GUS reporter gene driven by SeFAD2 promoter containing E- and G-Box motifs were co-expressed in developing sesame seeds. This co-expression revealed that SeCKI enhanced the SebHLH-mediated transactivation of the SeFAD2 gene promoter via phosphorylation of the SebHLH transcription factor.

Genomic structures and characterization of the 5′-flanking regions of acyl carrier protein and Δ4-palmitoyl-ACP desaturase genes from Coriandrum sativum

Kim, MJ; Shin, JS; Kim, JK; Suh, MC

Seed-specific expression of sesame microsomal oleic acid desaturase is controlled by combinatorial properties between negative cis-regulatory elements in the SeFAD2 promoter and enhancers in the 5′UTR intron

Kim, MJ; Kim, HJ; Shin, JS; Chung, CH; Ohlrogge, JB; Suh, MC

The SebHLH transcription factor mediates trans-activation of the SeFAD2 gene promoter through binding to E- and G-box elements

Kim, MJ; Kim, JK; Shin, JS; Suh, MC

Designer oils for better nutrition

Kinney, AJ

Manipulating desaturase activities in transgenic crop plants

Kinney, AJ; Cahoon, EB; Hitz, WD

DNA binding activity of the Arabidopsis G-box binding factor GBF1 is stimulated by phosphorylation by casein kinase II from broccoli

Induction of lipid and oleosin biosynthesis by (+)-abscisic acid and its metabolites in microspore-derived embryos of Brassica napus L. cv reston (biological responses in the presence of 8[prime]-hydroxy abscisic acid)